Native and nonnative reactions in ethanolamine ammonia-lyase are actuated by different dynamics.

ABSTRACT: We address the contribution of select classes of solvent-coupled configurational fluctuations to the complex choreography involved in configurational and chemical steps in an enzyme by comparing native and nonnative reactions conducted at different protein internal sites. The low temperature, first-order kinetics of covalent bond rearrangement of the cryotrapped substrate radical in coenzyme B₁₂-dependent ethanolamine ammonia-lyase (EAL) from Salmonella enterica display a kink, or increase in slope, of the Arrhenius plot with decreasing temperature. The event is associated with quenching of a select class of reaction-actuating collective fluctuations in the protein hydration layer. For comparison, a nonnative, radical reaction of the protein interior cysteine sulfhydryl group wi

SUBMITTER: Li W 

PROVIDER: S-EPMC10560697 | biostudies-literature | 2023 Oct

REPOSITORIES: biostudies-literature